1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185
|
NAME
perl5i - Fix as much of Perl 5 as possible in one pragma
SYNOPSIS
use perl5i::2;
or
$ perl5i your_script.pl
DESCRIPTION
Perl 5 has a lot of warts. There's a lot of individual modules and
techniques out there to fix those warts. perl5i aims to pull the best
of them together into one module so you can turn them on all at once.
This includes adding features, changing existing core functions and
changing defaults. It will likely not be 100% backwards compatible with
Perl 5, though it will be 99%, perl5i will try to have a lexical
effect.
Please add to this imaginary world and help make it real, either by
telling me what Perl looks like in your imagination
(http://github.com/evalEmpire/perl5i/issues) or make a fork (forking on
github is like a branch you control) and implement it yourself.
Rationale
Changing perl 5 core is a slow and difficult process. Perl 5 aims to be
compatible with ancient versions which means it is mostly stuck with
design, decisions and defaults made way back in the 90's.
There are modules in CPAN to solve or ease many of those issues but
many people don't know about them or don't know which ones to use.
Documentation and books are updated slowly and don't usually keep up;
this information becomes some sort of community knowledge, invisible
from the wider audience.
Even if you know a solution, having to decide everytime which module to
use and enable it individually might be enough for you to give up and
just do things the old way.
Perl5i brings all this community knowledge in a coherent way, in
something like 'the best of CPAN', enabled with a single command.
You don't need to know all it does nor how it does it, you just use
perl5i::2 on your code and you automatically get a modern environment,
with perl defaults, problems and inconsistencies fixed.
You can refer beginers to perl5i and they can benefit from it without
needing to become a perl guru first.
Using perl5i
Because perl5i plans to be incompatible in the future, you do not
simply use perl5i. You must declare which major version of perl5i you
are using. You do this like so:
# Use perl5i major version 2
use perl5i::2;
Thus the code you write with, for example, perl5i::2 will always remain
compatible even as perl5i moves on.
If you want to be daring, you can use perl5i::latest to get the latest
version. This will automatically happen if the program is -e. This lets
you do slightly less typing for one-liners like perl -Mperl5i -e ...
If you want your module to depend on perl5i, you should depend on the
versioned class. For example, depend on perl5i::2 and not perl5i.
See "VERSIONING" for more information about perl5i's versioning scheme.
What it does
perl5i enables each of these modules and adds/changes these functions.
We'll provide a brief description here, but you should look at each of
their documentation for full details.
The Meta Object
Every object (and everything is an object) now has a meta object
associated with it. Using the meta object you can ask things about the
object which were previously over complicated. For example...
# the object's class
my $class = $obj->mo->class;
# its parent classes
my @isa = $obj->mo->isa;
# the complete inheritance hierarchy
my @complete_isa = $obj->mo->linear_isa;
# the reference type of the object
my $reftype = $obj->mo->reftype;
A meta object is used to avoid polluting the global method space. mo
was chosen to avoid clashing with Moose's meta object.
See perl5i::Meta for complete details.
Subroutine and Method Signatures
perl5i makes it easier to declare what parameters a subroutine takes.
func hello($place) {
say "Hello, $place!\n";
}
method get($key) {
return $self->{$key};
}
method new($class: %args) {
return bless \%args, $class;
}
func and method define subroutines as sub does, with some extra
conveniences.
The signature syntax is currently very simple. The content will be
assigned from @_. This:
func add($this, $that) {
return $this + $that;
}
is equivalent to:
sub add {
my($this, $that) = @_;
return $this + $that;
}
method defines a method. This is the same as a subroutine, but the
first argument, the invocant, will be removed and made into $self.
method get($key) {
return $self->{$key};
}
sub get {
my $self = shift;
my($key) = @_;
return $self->{$key};
}
Methods have a special bit of syntax. If the first item in the
signature is $var: it will change the variable used to store the
invocant.
method new($class: %args) {
return bless \%args, $class;
}
is equivalent to:
sub new {
my $class = shift;
my %args = @_;
return bless \%args, $class;
}
Anonymous functions and methods work, too.
my $code = func($message) { say $message };
Guarantees include:
@_ will not be modified except by removing the invocant
Future versions of perl5i will add to the signature syntax and
capabilities. Planned expansions include:
Signature validation
Signature documentation
Named parameters
Required parameters
Read only parameters
Aliased parameters
Anonymous method and function declaration
Variable method and function names
Parameter traits
Traditional prototypes
See http://github.com/evalEmpire/perl5i/issues/labels/syntax#issue/19
for more details about future expansions.
The equivalencies above should only be taken for illustrative purposes,
they are not guaranteed to be literally equivalent.
Note that while all parameters are optional by default, the number of
parameters will eventually be enforced. For example, right now this
will work:
func add($this, $that) { return $this + $that }
say add(1,2,3); # says 3
The extra argument is ignored. In future versions of perl5i this will
be a runtime error.
Signature Introspection
The signature of a subroutine defined with func or method can be
queried by calling the signature method on the code reference.
func hello($greeting, $place) { say "$greeting, $place" }
my $code = \&hello;
say $code->signature->num_positional_params; # prints 2
Functions defined with sub will not have a signature.
See perl5i::Signature for more details.
Autoboxing
autobox allows methods to be defined for and called on most unblessed
variables. This means you can call methods on ordinary strings, lists
and hashes! It also means perl5i can add a lot of functionality without
polluting the global namespace.
autobox::Core wraps a lot of Perl's built in functions so they can be
called as methods on unblessed variables. @a->pop for example.
alias
$scalar_reference->alias( @identifiers );
@alias->alias( @identifiers );
%hash->alias( @identifiers );
(\&code)->alias( @identifiers );
Aliases a variable to a new global name.
my $code = sub { 42 };
$code->alias( "foo" );
say foo(); # prints 42
It will work on everything except scalar references.
our %stuff;
%other_hash->alias( "stuff" ); # %stuff now aliased to %other_hash
It is not a copy, changes to one will change the other.
my %things = (foo => 23);
our %stuff;
%things->alias( "stuff" ); # alias %things to %stuff
$stuff{foo} = 42; # change %stuff
say $things{foo}; # and it will show up in %things
Multiple @identifiers will be joined with '::' and used as the fully
qualified name for the alias.
my $class = "Some::Class";
my $name = "foo";
sub { 99 }->alias( $class, $name );
say Some::Class->foo; # prints 99
If there is just one @identifier and it has no "::" in it, the current
caller will be prepended. $thing->alias("name") is shorthand for
$thing->alias(CLASS, "name")
Due to limitations in autobox, non-reference scalars cannot be aliased.
Alias a scalar ref instead.
my $thing = 23;
$thing->alias("foo"); # error
my $thing = \23;
$thing->alias("foo"); # $foo is now aliased to $thing
This is basically a nicer way to say:
no strict 'refs';
*{$package . '::'. $name} = $reference;
Scalar Autoboxing
All of the methods provided by autobox::Core are available from perl5i.
in addition, perl5i adds some methods of its own.
path
my $object = $path->path;
Creates a Path::Tiny $object for the given file or directory $path.
my $path = "/foo/bar/baz.txt"->path;
my $content = $path->slurp;
center
my $centered_string = $string->center($length);
my $centered_string = $string->center($length, $character);
Centers $string between $character. $centered_string will be of length
$length.
$character defaults to " ".
say "Hello"->center(10); # " Hello ";
say "Hello"->center(10, '-'); # "---Hello--";
center() will never truncate $string. If $length is less than
$string->length it will just return $string.
say "Hello"->center(4); # "Hello";
round
my $rounded_number = $number->round;
Round to the nearest integer.
round_up
ceil
my $new_number = $number->round_up;
Rounds the $number towards infinity.
2.45->round_up; # 3
(-2.45)->round_up; # -2
ceil() is a synonym for round_up().
round_down
floor
my $new_number = $number->round_down;
Rounds the $number towards negative infinity.
2.45->round_down; # 2
(-2.45)->round_down; # -3
floor() is a synonyn for round_down().
is_number
$is_a_number = $thing->is_number;
Returns true if $thing is a number understood by Perl.
12.34->is_number; # true
"12.34"->is_number; # also true
"eleven"->is_number; # false
is_positive
$is_positive = $thing->is_positive;
Returns true if $thing is a positive number.
0 is not positive.
is_negative
$is_negative = $thing->is_negative;
Returns true if $thing is a negative number.
0 is not negative.
is_even
$is_even = $thing->is_even;
Returns true if $thing is an even integer.
is_odd
$is_odd = $thing->is_odd;
Returns true if $thing is an odd integer.
is_integer
$is_an_integer = $thing->is_integer;
Returns true if $thing is an integer.
12->is_integer; # true
12.34->is_integer; # false
"eleven"->is_integer; # false
is_int
A synonym for is_integer
is_decimal
$is_a_decimal_number = $thing->is_decimal;
Returns true if $thing is a decimal number.
12->is_decimal; # false
12.34->is_decimal; # true
".34"->is_decimal; # true
"point five"->is_decimal; # false
require
my $module = $module->require;
Will require the given $module. This avoids funny things like eval
qq[require $module] or die $@. It accepts only module names.
On failure it will throw an exception, just like require. On a success
it returns the $module. This is mostly useful so that you can
immediately call $module's import method to emulate a use.
# like "use $module qw(foo bar);" if that worked
$module->require->import(qw(foo bar));
# like "use $module;" if that worked
$module->require->import;
wrap
my $wrapped = $string->wrap( width => $cols, separator => $sep );
Wraps $string to width $cols, breaking lines at word boundries using
separator $sep.
If no width is given, $cols defaults to 76. Default line separator is
the newline character "\n".
See Text::Wrap for details.
ltrim
rtrim
trim
my $trimmed = $string->trim;
my $trimmed = $string->trim($character_set);
Trim whitespace. ltrim() trims off the start of the string (left),
rtrim() off the end (right) and trim() off both the start and end.
my $string = ' testme'->ltrim; # 'testme'
my $string = 'testme '->rtrim; # 'testme'
my $string = ' testme '->trim; # 'testme'
They all take an optional $character_set which will determine what
characters should be trimmed. It follows regex character set syntax so
A-Z will trim everything from A to Z. Defaults to \s, whitespace.
my $string = '-> test <-'->trim('-><'); # ' test '
title_case
my $name = 'joe smith'->title_case; # Joe Smith
Will uppercase every word character that follows a wordbreak character.
path2module
my $module = $path->path2module;
Given a relative $path it will return the Perl module this represents.
For example,
"Foo/Bar.pm"->path2module; # "Foo::Bar"
It will throw an exception if given something which could not be a path
to a Perl module.
module2path
my $path = $module->module2path;
Will return the relative $path in which the Perl $module can be found.
For example,
"Foo::Bar"->module2path; # "Foo/Bar.pm"
is_module_name
my $is_valid = $string->is_module_name;
Will return true if the $string is a valid module name.
"Foo::Bar"->is_module_name; # true
"Foo/Bar"->is_module_name; # false
group_digits
my $number_grouped = $number->group_digits;
my $number_grouped = $number->group_digits(\%options);
Turns a number like 1234567 into a string like 1,234,567 known as
"digit grouping".
It honors your current locale to determine the separator and grouping.
This can be overridden using %options.
NOTE: many systems do not have their numeric locales set properly
separator
The character used to separate groups. Defaults to "thousands_sep" in
your locale or "," if your locale doesn't specify.
decimal_point
The decimal point character. Defaults to "decimal_point" in your
locale or "." if your locale does not specify.
grouping
How many numbers in a group? Defaults to "grouping" in your locale or
3 if your locale doesn't specify.
Note: we don't honor the full grouping locale, its a wee bit too
complicated.
currency
If true, it will treat the number as currency and use the monetary
locale settings. "mon_thousands_sep" instead of "thousands_sep" and
"mon_grouping" instead of "grouping".
1234->group_digits; # 1,234 (assuming US locale)
1234->group_digits( separator => "." ); # 1.234
commify
my $number_grouped = $number->commify;
my $number_grouped = $number->commify(\%options);
commify() is just like group_digits() but it is not locale aware. It is
useful when you want a predictable result regardless of the user's
locale settings.
%options defaults to ( separator => ",", grouping => 3, decimal_point
=> "." ). Each key will be overridden individually.
1234->commify; # 1,234
1234->commify({ separator => "." }); # 1.234
reverse
my $reverse = $string->reverse;
Reverses a $string.
Unlike Perl's reverse(), this always reverses the string regardless of
context.
Array Autoboxing
The methods provided by "Array Methods" in autobox::Core are available
from perl5i.
All the functions from List::Util and select ones from List::MoreUtils
are all available as methods on unblessed arrays and array refs: first,
max, maxstr, min, minstr, minmax, shuffle, reduce, sum, any, all, none,
true, false, uniq and mesh.
They have all been altered to return array refs where applicable in
order to allow chaining.
@array->grep(sub{ $_->is_number })->sum->say;
foreach
@array->foreach( func($item) { ... } );
Works like the built in foreach, calls the code block for each element
of @array passing it into the block.
@array->foreach( func($item) { say $item } ); # print each item
It will pass in as many elements as the code block accepts. This allows
you to iterate through an array 2 at a time, or 3 or 4 or whatever.
my @names = ("Joe", "Smith", "Jim", "Dandy", "Jane", "Lane");
@names->foreach( func($fname, $lname) {
say "Person: $fname $lname";
});
A normal subroutine with no signature will get one at a time.
If @array is not a multiple of the iteration (for example, @array has 5
elements and you ask 2 at a time) the behavior is currently undefined.
as_hash
my %hash = @array->as_hash;
This method returns a %hash where each element of @array is a key. The
values are all true. Its functionality is similar to:
my %hash = map { $_ => 1 } @array;
Example usage:
my @array = ("a", "b", "c");
my %hash = @array->as_hash;
say q[@array contains 'a'] if $hash{"a"};
pick
my @rand = @array->pick($number);
The pick() method returns a list of $number elements in @array. If
$number is larger than the size of the list, it returns the entire list
shuffled.
Example usage:
my @array = (1, 2, 3, 4);
my @rand = @array->pick(2);
pick_one
my $rand = @array->pick_one;
The pick_one() method returns a random element in @array. It is similar
to @array->pick(1), except that it does not return a list.
Example usage:
my @array = (1,2,3,4);
my $rand = @array->pick_one;
diff
Calculate the difference between two (or more) arrays:
my @a = ( 1, 2, 3 );
my @b = ( 3, 4, 5 );
my @diff_a = @a->diff(\@b) # [ 1, 2 ]
my @diff_b = @b->diff(\@a) # [ 4, 5 ]
Diff returns all elements in array @a that are not present in array @b.
Item order is not considered: two identical elements in both arrays
will be recognized as such disregarding their index.
[ qw( foo bar ) ]->diff( [ qw( bar foo ) ] ) # empty, they are equal
For comparing more than two arrays:
@a->diff(\@b, \@c, ... )
All comparisons are against the base array (@a in this example). The
result will be composed of all those elements that were present in @a
and in none other.
It also works with nested data structures; it will traverse them
depth-first to assess whether they are identical or not. For instance:
[ [ 'foo ' ], { bar => 1 } ]->diff([ 'foo' ]) # [ { bar => 1 } ]
In the case of overloaded objects (i.e., DateTime, URI, Path::Class,
etc.), it tries its best to treat them as strings or numbers.
my $uri = URI->new("http://www.perl.com");
my $uri2 = URI->new("http://www.perl.com");
[ $uri ]->diff( [ "http://www.perl.com" ] ); # empty, they are equal
[ $uri ]->diff( [ $uri2 ] ); # empty, they are equal
popn
my @newarray = @array->popn($n);
Pops $n values from the @array.
If $n is greater than the length of @array, it will return the whole
@array. If $n is 0, it will return an empty array.
A negative $n or non-integer is an error.
my @array = (1, 2, 3, 4, 5);
my @newarray = @array->popn(3); # (3, 4, 5)
shiftn
my @newarray = @array->shiftn($n);
Works like popn, but it shifts off the front of the array instead of
popping off the end.
my @array = (1, 2, 3, 4, 5);
my @newarray = @array->shiftn(3); # (1, 2, 3)
intersect
my @a = (1 .. 10);
my @b = (5 .. 15);
my @intersection = @a->intersect(\@b) # [ 5 .. 10 ];
Performs intersection between arrays, returning those elements that are
present in all of the argument arrays simultaneously.
As with diff(), it works with any number of arrays, nested data
structures of arbitrary depth, and handles overloaded objects
graciously.
ltrim
rtrim
trim
my @trimmed = @list->trim;
my @trimmed = @list->trim($character_set);
Trim whitespace from each element of an array. Each works just like
their scalar counterpart.
my @trimmed = [ ' foo', 'bar ' ]->ltrim; # [ 'foo', 'bar ' ]
my @trimmed = [ ' foo', 'bar ' ]->rtrim; # [ ' foo', 'bar' ]
my @trimmed = [ ' foo', 'bar ' ]->trim; # [ 'foo', 'bar' ]
As with the scalar trim() methods, they all take an optional
$character_set which will determine what characters should be trimmed.
my @trimmed = ['-> foo <-', '-> bar <-']->trim('-><'); # [' foo ', ' bar ']
Hash Autoboxing
All of the methods provided by "Hash Methods" in autobox::Core are
available from perl5i.
In addition...
each
Iterate through each key/value pair in a hash using a callback.
my %things = ( foo => 23, bar => 42 );
%things->each( func($k, $v) {
say "Key: $k, Value: $v"
});
Unlike the each function, individual calls to each are guaranteed to
iterate through the entirety of the hash.
flip
Exchanges values for keys in a hash.
my %things = ( foo => 1, bar => 2, baz => 5 );
my %flipped = %things->flip; # { 1 => foo, 2 => bar, 5 => baz }
If there is more than one occurrence of a certain value, any one of the
keys may end up as the value. This is because of the random ordering of
hash keys.
# Could be { 1 => foo }, { 1 => bar }, or { 1 => baz }
{ foo => 1, bar => 1, baz => 1 }->flip;
Because hash references cannot usefully be keys, it will not work on
nested hashes.
{ foo => [ 'bar', 'baz' ] }->flip; # dies
merge
Recursively merge two or more hashes together using
Hash::Merge::Simple.
my $a = { a => 1 };
my $b = { b => 2, c => 3 };
$a->merge($b); # { a => 1, b => 2, c => 3 }
For conflicting keys, rightmost precedence is used:
my $a = { a => 1 };
my $b = { a => 100, b => 2};
$a->merge($b); # { a => 100, b => 2 }
$b->merge($a); # { a => 1, b => 2 }
It also works with nested hashes, although it won't attempt to merge
array references or objects. For more information, look at the
Hash::Merge::Simple docs.
diff
my %staff = ( bob => 42, martha => 35, timmy => 23 );
my %promoted = ( timmy => 23 );
%staff->diff(\%promoted); # { bob => 42, martha => 35 }
Returns the key/value pairs present in the first hash that are not
present in the subsequent hash arguments. Otherwise works as
@array->diff.
intersect
%staff->intersect(\%promoted); # { timmy => 23 }
Returns the key/value pairs that are present simultaneously in all the
hash arguments. Otherwise works as @array->intersect.
Code autoboxing
signature
my $sig = $code->signature;
You can query the signature of any code reference defined with func or
method. See "Signature Introspection" for details.
If $code has a signature, returns an object representing $code's
signature. See perl5i::Signature for details. Otherwise it returns
nothing.
caller
Perl6::Caller causes caller to return an object in scalar context.
die
die now always returns an exit code of 255 instead of trying to use $!
or $? which makes the exit code unpredictable. If you want to exit with
a message and a special exit code, use warn then exit.
list
list will force list context similar to how scalar will force scalar
context.
utf8::all
perl5i turns on utf8::all which turns on all the Unicode features of
Perl it can.
Here is the current list, more may be turned on later.
Bare strings in your source code are now UTF8. This means UTF8 variable
and method names, strings and regexes.
my $message = "انا لا اتكلم العربيه";
my $τάδε = "It's all Greek to me!";
sub fünkßhüñ { ... }
Strings will be treated as a set of characters rather than a set of
bytes. For example, length will return the number of characters, not
the number of bytes.
length("perl5i is MËTÁŁ"); # 15, not 18
@ARGV will be read as UTF8.
STDOUT, STDIN, STDERR and all newly opened filehandles will have UTF8
encoding turned on. Consequently, if you want to output raw bytes to a
file, such as outputting an image, you must set binmode $fh.
capture
my($stdout, $stderr) = capture { ... } %options;
my $stdout = capture { ... } %options;
capture() lets you capture all output to STDOUT and STDERR in any block
of code.
# $out = "Hello"
# $err = "Bye"
my($out, $err) = capture {
print "Hello";
print STDERR "Bye";
};
If called in scalar context, it will only return STDOUT and silence
STDERR.
# $out = "Hello"
my $out = capture {
print "Hello";
warn "oh god";
};
capture takes some options.
tee
tee will cause output to be captured yet still printed.
my $out = capture { print "Hi" } tee => 1;
merge
merge will merge STDOUT and STDERR into one variable.
# $out = "HiBye"
my $out = capture {
print "Hi";
print STDERR "Bye";
} merge => 1;
Carp
croak and carp from Carp are always available.
The Carp message will always format consistently, smoothing over the
backwards incompatible change in Carp 1.25.
Child
Child provides the child function which is a better way to do forking.
child creates and starts a child process, and returns an
Child::Link::Proc object which is a better interface for managing the
child process. The only required argument is a codeblock, which is
called in the new process. exit() is automatically called for you after
the codeblock returns.
my $proc = child {
my $parent = shift;
...
};
You can also request a pipe for IPC:
my $proc = child {
my $parent = shift;
$parent->say("Message");
my $reply = $parent->read();
...
} pipe => 1;
my $message = $proc->read();
$proc->say("reply");
See Child for more information.
English
English gives English names to the punctuation variables; for instance,
<$@> is also <$EVAL_ERROR>. See perlvar for details.
It does not load the regex variables which affect performance.
$PREMATCH, $MATCH, and $POSTMATCH will not exist. See the p modifier in
perlre for a better alternative.
Modern::Perl
Modern::Perl turns on strict and warnings, enables all the 5.10
features like given/when, say and state, and enables C3 method
resolution order.
CLASS
Provides CLASS and $CLASS alternatives to __PACKAGE__.
File::chdir
File::chdir gives you $CWD representing the current working directory
and it's assignable to chdir. You can also localize it to safely chdir
inside a scope.
File::stat
File::stat causes stat to return an object in scalar context.
DateTime
time, localtime, and gmtime are replaced with DateTime objects. They
will all act like the core functions.
# Sat Jan 10 13:37:04 2004
say scalar gmtime(2**30);
# 2004
say gmtime(2**30)->year;
# 2009 (when this was written)
say time->year;
Time::y2038
gmtime() and localtime() will now safely work with dates beyond the
year 2038 and before 1901. The exact range is not defined, but we
guarantee at least up to 2**47 and back to year 1.
IO::Handle
Turns filehandles into objects so you can call methods on them. The
biggest one is autoflush rather than mucking around with $| and select.
$fh->autoflush(1);
autodie
autodie causes system and file calls which can fail (open, system, and
chdir, for example) to die when they fail. This means you don't have to
put or die at the end of every system call, but you do have to wrap it
in an eval block if you want to trap the failure.
autodie's default error messages are pretty smart.
All of autodie will be turned on.
autovivification
autovivification fixes the bug/feature where this:
$hash = {};
$hash->{key1}{key2};
Results in $hash->{key1} coming into existence. That will no longer
happen.
No indirect object syntax
perl5i turns indirect object syntax, ie. new $obj, into a compile time
error. Indirect object syntax is largely unnecessary and removing it
avoids a number of ambiguous cases where Perl will mistakenly try to
turn a function call into an indirect method call.
See indirect for details.
want
want() generalizes the mechanism of the wantarray function, allowing a
function to determine the context it's being called in. Want
distinguishes not just scalar v. array context, but void, lvalue,
rvalue, boolean, reference context, and more. See perldoc Want for full
details.
Try::Tiny
Try::Tiny gives support for try/catch blocks as an alternative to eval
BLOCK. This allows correct error handling with proper localization of
$@ and a nice syntax layer:
# handle errors with a catch handler
try {
die "foo";
} catch {
warn "caught error: $_";
};
# just silence errors
try {
die "foo";
};
See perldoc Try::Tiny for details.
true
You no longer have to put a true value at the end of a module which
uses perl5i.
Better load errors
Most of us have learned the meaning of the dreaded "Can't locate Foo.pm
in @INC". Admittedly though, it's not the most helpful of the error
messages. In perl5i we provide a much friendlier error message.
Example:
Can't locate My/Module.pm in your Perl library. You may need to install it
from CPAN or another repository. Your library paths are:
Indented list of paths, 1 per line...
Turning off features
use perl5i::2 -skip => \@features_to_skip;
While perl5i is intended as a curated collection of modules, its
possible you might not want certain features. Features can be turned
off in your scope by using -skip.
For example, this will skip loading Try::Tiny.
use perl5i::latest -skip => [qw(Try::Tiny)];
Why would you do this? You might want to use a different try/catch
module such as TryCatch which provides its own try and catch.
The feature strings are: autobox, autodie, autovivification, capture,
Carp::Fix::1_25, Child, CLASS, die, English, File::chdir, indirect,
list, Meta, Modern::Perl, Perl6::Caller, Signatures, stat, time, true,
Try::Tiny, utf8::all, Want.
Command line program
There is a perl5i command line program installed with perl5i (Windows
users get perl5i.bat). This is handy for writing one liners.
perl5i -e 'gmtime->year->say'
And you can use it on the #! line.
#!/usr/bin/perl5i
gmtime->year->say;
If you write a one-liner without using this program, saying -Mperl5i
means -Mperl5i::latest. Please see "Using perl5i" and "VERSIONING" for
details.
BUGS
Some parts are not lexical. Some parts are package scoped.
If you're going to use two versions of perl5i together, we do not
currently recommend having them in the same package.
See http://github.com/evalEmpire/perl5i/issues/labels/bug for a
complete list.
Please report bugs at http://github.com/evalEmpire/perl5i/issues/.
VERSIONING
perl5i follows the Semantic Versioning policy, http://semver.org. In
short...
Versions will be of the form X.Y.Z.
0.Y.Z may change anything at any time.
Incrementing X (ie. 1.2.3 -> 2.0.0) indicates a backwards incompatible
change.
Incrementing Y (ie. 1.2.3 -> 1.3.0) indicates a new feature.
Incrementing Z (ie. 1.2.3 -> 1.2.4) indicates a bug fix or other
internal change.
NOTES
Inspired by chromatic's Modern::Perl and in particular
http://www.modernperlbooks.com/mt/2009/04/ugly-perl-a-lesson-in-the-importance-of-language-design.html.
I totally didn't come up with the "Perl 5 + i" joke. I think it was
Damian Conway.
THANKS
Thanks to our contributors: Chas Owens, Darian Patrick, rjbs,
chromatic, Ben Hengst, Bruno Vecchi and anyone else I've forgotten.
Thanks to Flavian and Matt Trout for their signature and Devel::Declare
work.
Thanks to all the CPAN authors upon whom this builds.
LICENSE
Copyright 2009-2010, Michael G Schwern <schwern@pobox.com>
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
See http://dev.perl.org/licenses/artistic.html
SEE ALSO
Repository: http://github.com/evalEmpire/perl5i/ Issues/Bugs:
http://github.com/evalEmpire/perl5i/issues IRC: irc://irc.perl.org on
the #perl5i channel Wiki: http://github.com/evalEmpire/perl5i/wiki
Twitter: http://twitter.com/perl5i
Frequently Asked Questions about perl5i: perl5ifaq
Some modules with similar purposes include: Modern::Perl, Common::Sense
For a complete object declaration system, see Moose and
MooseX::Declare.
|